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3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 193 · 40 questions
TalentJR

How to do it in your head (Hundreds first): Keep the first number as it is and split the second into hundreds, tens and ones. Add (or take away) the hundreds first, then the tens. Finish with the ones — bridge through a ten if you need to.

NameDateTime takenScore ___ / 40
  1. 1.857 − 384 =
  2. 2.244 + 573 =
  3. 3.445 − 141 =
  4. 4.811 − 532 =
  5. 5.481 − 255 =
  6. 6.516 − 335 =
  7. 7.939 − 531 =
  8. 8.160 + 641 =
  9. 9.811 − 231 =
  10. 10.413 − 121 =
  11. 11.718 + 239 =
  12. 12.503 + 542 =
  13. 13.527 + 511 =
  14. 14.787 + 187 =
  15. 15.468 − 261 =
  16. 16.172 + 358 =
  17. 17.133 + 343 =
  18. 18.430 − 147 =
  19. 19.617 − 481 =
  20. 20.138 + 566 =
  21. 21.655 + 467 =
  22. 22.771 + 541 =
  23. 23.623 − 193 =
  24. 24.572 − 183 =
  25. 25.205 + 211 =
  26. 26.533 − 331 =
  27. 27.983 − 855 =
  28. 28.753 + 612 =
  29. 29.261 + 611 =
  30. 30.951 − 325 =
  31. 31.833 − 455 =
  32. 32.472 − 305 =
  33. 33.679 − 356 =
  34. 34.299 + 167 =
  35. 35.906 − 781 =
  36. 36.228 + 571 =
  37. 37.984 − 521 =
  38. 38.708 − 157 =
  39. 39.519 + 355 =
  40. 40.763 − 499 =

Answer key

  1. 473
  2. 817
  3. 304
  4. 279
  5. 226
  6. 181
  7. 408
  8. 801
  9. 580
  10. 292
  11. 957
  12. 1045
  13. 1038
  14. 974
  15. 207
  16. 530
  17. 476
  18. 283
  19. 136
  20. 704
  21. 1122
  22. 1312
  23. 430
  24. 389
  25. 416
  26. 202
  27. 128
  28. 1365
  29. 872
  30. 626
  31. 378
  32. 167
  33. 323
  34. 466
  35. 125
  36. 799
  37. 463
  38. 551
  39. 874
  40. 264

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